michael@0: /*
michael@0:  * ====================================================================
michael@0:  * Licensed to the Apache Software Foundation (ASF) under one
michael@0:  * or more contributor license agreements.  See the NOTICE file
michael@0:  * distributed with this work for additional information
michael@0:  * regarding copyright ownership.  The ASF licenses this file
michael@0:  * to you under the Apache License, Version 2.0 (the
michael@0:  * "License"); you may not use this file except in compliance
michael@0:  * with the License.  You may obtain a copy of the License at
michael@0:  *
michael@0:  *   http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing,
michael@0:  * software distributed under the License is distributed on an
michael@0:  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
michael@0:  * KIND, either express or implied.  See the License for the
michael@0:  * specific language governing permissions and limitations
michael@0:  * under the License.
michael@0:  * ====================================================================
michael@0:  *
michael@0:  * This software consists of voluntary contributions made by many
michael@0:  * individuals on behalf of the Apache Software Foundation.  For more
michael@0:  * information on the Apache Software Foundation, please see
michael@0:  * <http://www.apache.org/>.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: package ch.boye.httpclientandroidlib.conn.routing;
michael@0: 
michael@0: import ch.boye.httpclientandroidlib.HttpException;
michael@0: import ch.boye.httpclientandroidlib.HttpHost;
michael@0: import ch.boye.httpclientandroidlib.HttpRequest;
michael@0: import ch.boye.httpclientandroidlib.protocol.HttpContext;
michael@0: 
michael@0: /**
michael@0:  * Encapsulates logic to compute a {@link HttpRoute} to a target host.
michael@0:  * Implementations may for example be based on parameters, or on the
michael@0:  * standard Java system properties.
michael@0:  * <p>
michael@0:  * Implementations of this interface must be thread-safe. Access to shared
michael@0:  * data must be synchronized as methods of this interface may be executed
michael@0:  * from multiple threads.
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: public interface HttpRoutePlanner {
michael@0: 
michael@0:     /**
michael@0:      * Determines the route for a request.
michael@0:      *
michael@0:      * @param target    the target host for the request.
michael@0:      *                  Implementations may accept <code>null</code>
michael@0:      *                  if they can still determine a route, for example
michael@0:      *                  to a default target or by inspecting the request.
michael@0:      * @param request   the request to execute
michael@0:      * @param context   the context to use for the subsequent execution.
michael@0:      *                  Implementations may accept <code>null</code>.
michael@0:      *
michael@0:      * @return  the route that the request should take
michael@0:      *
michael@0:      * @throws HttpException    in case of a problem
michael@0:      */
michael@0:     public HttpRoute determineRoute(HttpHost target,
michael@0:                                     HttpRequest request,
michael@0:                                     HttpContext context) throws HttpException;
michael@0: 
michael@0: }